Using chapters 29 and 30, which are concerned with the issue of
secure communication, as a starting point, the May/June 2000 issue
of Technology Review contained an intriguing article on quantum
computing.
Physicist Issac Chuang believes quantum computing is the way to
understand what information is in a physical sense and what physics
is in terms of information.
While conventional computers follow the rules of binary logic,
governed by strict eeither-or distinction for each bit of data, at
the level of individual subatomic particles such as electrons, which
can rotate clockwise or counter clockwise, are in effect undecided.
Without accurate measurement you could not for sure. These quantum
particles, called quibits, could simultaneously exist as "both" and
"and" from a logical point of view. Two quibits co-existing could
represent a combination of all possible two-bit numbers,ie: (00,01,
10,11).
The time required for conventional computers to factor growing
numbers, increases exponentially, regardless of how creatively the
algorithms are manipulated. To get an idea of the vast amount of
time this is, the article states that to factor beyond a few hundred
digits, even the fastest computers available today would exceed the
lifetime of the universe, while a quantum machine would need a mere
12 months to factor a 400 digit number. Awesome!
Now that quantum computing appears to be more of a reality in
the lab, the National Security Agency, the Pentagon and cryptographers
around the world are realizing that codes once believed to be
"unbreakable" might now be decrypted.
